Mercedes-Benz Forum banner

1 - 13 of 13 Posts

·
Registered
1998 C230
Joined
·
8 Posts
Discussion Starter #1
My car has 117k miles and to my knowledge it's never had the spark plugs changed (bought it used so no real service info). However, due to the loss of power, low FE, and occasional misfiring I'm assuming that the old plugs are the cause of all the problems.

So when I looked under the hood I realized I have no idea how to get access to the spark plugs. Do i have to remove the engine's air intake and remove the shroud?

If you're unfamiliar with my car here are some pics I found on the forum

Also, I was wondering if you guys recommend Platinum or Iridium plugs, copper sounds a bit too cheap to use on a benz, but I'm really not sure so whatever you guys suggest is what I'll end up using

Thanks in advance guys!
 

·
Registered
c36, 1970 LeMans Sport, a truck
Joined
·
318 Posts
intake across the valve cover comes off and the removable panel under it has the plugs.

Don't mess around with "upgraded" plugs. Use what the factory recommends. Never pays off.

rjp
 

·
Registered
1995 C280
Joined
·
272 Posts
While you're in there, I would suggest replacing the rubber tubes that connect the coil packs to the plugs. They are cheap $`0 a piece I think and you need 3 of them. If it's been that long since the plugs were changed, I'll guarantee those suckers will probably be torn or tear when you take the coils and plugs out. When replacing everything, make sure you tighten the cover from the middle out. there are 6 hex head bolts. When I replaced the plugs and rubber connectors, I kept tightening unevenly and I think it was moving one of the outer coils enough to to cause really rough running. I ended up doing the inner 2 then moved out alternating from front to back.
 

·
Registered
95 C280, 89 300E, 94' E320 Coupe, 91' 560SEC
Joined
·
1,095 Posts
While you're in there, I would suggest replacing the rubber tubes that connect the coil packs to the plugs. They are cheap $`0 a piece I think and you need 3 of them. If it's been that long since the plugs were changed, I'll guarantee those suckers will probably be torn or tear when you take the coils and plugs out. When replacing everything, make sure you tighten the cover from the middle out. there are 6 hex head bolts. When I replaced the plugs and rubber connectors, I kept tightening unevenly and I think it was moving one of the outer coils enough to to cause really rough running. I ended up doing the inner 2 then moved out alternating from front to back.

His profile reads that its a 230 so i think he might have 2 coil pack boots. I agree those boots will be shot, dry and brittle Also do torque the plugs to spec w/torque wrench. DO NOT OVER TIGHTEN the plug will then be further below the cylinder area or the plug will sheer off
 

·
Registered
1998 C230
Joined
·
8 Posts
Discussion Starter #5 (Edited)
His profile reads that its a 230 so i think he might have 2 coil pack boots. I agree those boots will be shot, dry and brittle Also do torque the plugs to spec w/torque wrench. DO NOT OVER TIGHTEN the plug will then be further below the cylinder area or the plug will sheer off
Thanks guys for your replies, but I've just got a few more questions, so bear with me.

Why would my vehicle require two sets of coil pack boots, does this mean its two per cylinder, or two out of the 4 cyl? If the later is the case, which two cyls need the boots? and what would the torque spec for my vehicle be, would I be safe to assume that hand tightened and then a few cranks with a regular socket wrench would suffice?

Thanks again in advance for all of your help.
 

·
Registered
1998 C230
Joined
·
8 Posts
Discussion Starter #6
Sorry for re-bumping my own thread, but I was also wondering about the gap on the plugs. I just purchased some that have a .038 gap, whats the OEM standard for the C230?
 

·
Registered
95 C280, 89 300E, 94' E320 Coupe, 91' 560SEC
Joined
·
1,095 Posts
At work and don't have the spec sheets on me. Sunday I'll probably have the info. Yes the coil pack typically have two cyl to a pack. The pack rests directly on one spark plug via a boot and then a spark plug wire connects from the coil to the other cylinder plug
 

·
Registered
1998 C230
Joined
·
8 Posts
Discussion Starter #10
Hey everyone!

Just got a chance to finally get that cover off today. Anyway I got in there and it looks like the wires aren't too old. Probably been changed once before. The problem I'm having is that I can't seem to get the damn red plugs out. Maybe the engine wasn't cooled off enough, but they seemed to want to stay in there. Does it normally require a decent amount of force? I'm trying not to break it because my local auto parts store says it'll take a week to get the wires in stock.


Also, when I took the air intake off I ripped a hose that went from the intake to the engine block. Anyone know where I can get a replacement? For now its electric taped together along the rip but I don't think it can stay that way for long.



Thanks again for all your help. I know it can be frustrating to help a newbie so thanks :cool:
 

·
Registered
1998 c230 170K
Joined
·
1,415 Posts
That tube is about 5 bucks even from the stealer, just get another. If your having problems getting the boot off just disconnect the wire to the coil. Usually after that you will have enough access to take the spark plug boot portion off. You can slightly push the red part (top) from side to side then pull up on the boot to pull up in on piece. B
 

·
Registered
1999 C230 Kompressor, Midnight Blue
Joined
·
25 Posts
I'm pretty sure that's the crankcase ventilation hose. Thought it might help when you are explaining to the stealer what you need.

Take it w/ a grain of salt tho - I have a 99 c230k, and its laid out a little different.
 

·
Registered
c36, 1970 LeMans Sport, a truck
Joined
·
318 Posts
check the wires with a ohmmeter and see if they are consistent between them- most likely, they are fine and will last life of the car. They are just copper unshielded wires with resistors at the end, and they typically don't fail unless you abuse them or oil soak 'em.

And ya, new boots under the coils, no exceptions every time the coil comes out.

rjp
 
1 - 13 of 13 Posts
Top